Tube perforator



G. K. HALE ETAL 3,491,639

TUBE PERFORATOR Jan. 27, 1970 Filed April 29. 1968 2 Sheets-Sheet l mvanrons GERALD K. HALE ARTHUR W. HALE REGINALD. D. HALE Jan. 27, 1970 G. K. HALE ETAL TUBE PERFORATOR 2 Sheets-Sheet 2 Filed April 29. 1968 INVEN-roRs GERALD K. HALE ARTHUR w. HALE ALE REGINALD D. H

ATTORNEYS United States Patent O U.S. Cl. 83--179 21 Claims ABSTRACT OF THE DISCLOSURE A tube perforator wherein a tube to be perforated is releasably gripped between complimentary operator controlled hydraulically operated gripping members through which punches slidably extend. A swinging hammer, driven by a power operated rotating cam, 1s .arranged to strike the punches when swung in one direction so as. to drive the latter to an extended punching position relative to the gripping members, and when swung in the opposite direction to strike a retractor connected to the punches so as to retract the latter, thereby permit the operator to release the gripping member and reposition the tube for another punching operation.

BACKGROUND OF THE INVENTION This invention relates to apparatus for perforating tubes of relatively large diameter. In the production of perforated, particularly thin-walled tubes of relatively large diameter, a punching operation must be carried out very caefully so as to prevent the collapse or deformation of the tubes under the pressure of the punches. Furthermore, production of perforated tubes in order to meet oompetition must be done expeditiously and at very little cost.

These requirements, particularly the requirement for careful operation has resulted in the development of varied types of punching equipment, however, such equipment has, in the main, been very cumbersome to use, requiring the employment of a relatively large number of personnel and has been a relatively slow operation.

SUMMARY OF THE INVENTION The present invention provides a perforator wherein the moving of component parts is performed with the use of powered equipment and which is semi-automatic, thereby permitting the punching operation to be carried out in a very speedy manner with the use of very few personnel. The cost of a punching operation is therefore relatively low.

The present invention, furthermore, includes means whereby the punching operation although carried out in a very seedy manner can be done with utmost safety.

The present invention, furthermore, includes a novel arrangement of operational components for translating rotary moti-on to lineal motion and which, after each punching operation, is completed, automatically adjusts the tube lineally when the latter is rotatably adjusted for a subsequent punching operation.

For attaining these ends the present invention com prises a supporting frame, rst and second tube engaging members mounted in confronting relationship on the frame for relative movement, said members having arcuately shaped inner faces in confronting relationship for intimately engaging and holding a tube to be perforated, one of the members having at least one guide passage extending therethrough radially of the inner face thereof, a punch slidably located in the guide passage 3,491,639 Patented Jan. 27, 1970 ICC for movement between extended and retracted positions relative to the inner face of said one member, a punch carrier slidably supported on the frame for movement in the direction of movement of the punch and being operably connected t-o the latter, a retractor operably connected to the punch carrier, a hammer member swingably mounted on the frame for operation between the carrier and retractor, said hammer member being adapted when swung in one direction to strike the carrier and move the punch to its extending position and when swung in the opposite direction to strike the retractor so as to move the carrier and with it the punch to its retracted position, and operator controlled means for operating the hammer member.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is an end view of the apparatus,

FIGURE 2 is an enlarged isometric view of a portion of the apparatus,

FIGURE 3 is an enlarged sectional view taken Online 3 3 of FIGURE 2,

FIGURE 4 is a sectional view taken on line 4-4 of FIGURE 3,

FIGURE 5 is an enlarged sectional view taken on line 5-5 of FIGURE 2, and

FIGURE 6 is an isometric view of an internal tube support.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGURE 1 of the drawings, the numeral 10 designates a supporting frame which may be in the form of a table having a top 11 and legs 12, suitable brace elements 13 being employed to provide structural rigidity.

A pair of elongated guide columns 15 and 16 lare rigidly mounted in a spaced apart vertical position on the table top 11. These columns may be connected to the table top as by welding -or the like or by any other suitable means. A cap 17 extends between the upper ends 18 and 19 of columns 15 and 16, respectively, said upper ends having reduced threaded portions which extend through suitable apertures 20 formed through the cap, nuts 21 being threaded over said threaded portion to rmly secure the cap thereto. Guide sleeves 23 and 24 are slidably mounted on columns 15 and 16, respectively, and secured between the guide sleeves and connected thereto is a carrier plate 25. This carrier plate is movable vertically by means of a conventional double-acting hydraulic piston and cylinder assembly 28, the piston 29 thereof being secured to the carrier plate and the cylinder 30 thereof being secured to the cap 17. Conduits 3 extend from the cylinder 30 and are connected to an operator controlled source of pressurized hydraulic fluid, not shown.

An upper gripping or engaging member comprising a pair of tube gripping elements and 36 are secured in a depending position to the carrier plate 25 by means of machine bolts 38 extending through suitably slotted holes 39 formed in the carrier plate and extending into threaded holes, not shown, in said elements 35 and 36, the connection permitting limited lateral adjustment of said elements relative to the carrier plate.

These elements 35 and 36 are of identical design preferably formed of relatively wide steel blocks having downwardly facing arcuate inner faces 42 and 43, respectively, the radius of curvature of the latter being the same as that of a tube 45 to bepunched. The length of curve of each of the arcuate inner faces 42 and 43 is just a little less than one-quarter of the circumferential length of the tube 45.

Mounted on the table top 11 is a lower gripping member 49 comprising a pair of tube gripping elements 50 and SIL'These elements 50 and 51 are substantially identical in shape to elements 35 and 36 having arcuate inner faces 53 and 54 respectively having the same radius of curvature and arcuate length as inner face 42 and 43. The elements 50 and 51 are provided with base flanges 55 and 56, respectively, through which slotted holes 57 and S8, respectively, are formed to permit the insertion of machine bolts 60 therethrough, said bolts being screwed into suitably tapped holes, not shown, formed in the table top. This connection also permits limited lateral adjustment of said elements 50 and 51, and further permits them to be positioned relative to each other so that their inner faces lie on the circumference of a common circle having a radius equal to the externai radius of the tube to be punched. Both sets of gripping elements 35, 36 and -0, 51 are arranged so as to complement each other whereby the upper and lower gripping members may be relatively moved into intimate holding engagement with tube 45 by means of the operation of the piston and cylinder assembly.

The gripping elements 50y and 51 serve as guides for punches by means of which a tube rmly gripped by both pairs of elements 35, 36'and 50, 51, may be perforated. As the elements 50 and 51 are identical and as their associated punches and punch operating mechanism are also identical, only element 50 and its associated punches and punching mechanism 52 will be described in detail.

Formed through element 50 are a plurality of axially parallel punch guide passages 66 (see FIGURE 2). These passages usually are circular in cross section and open inwardly through inner face 53 and outwardly through a Hat planar outer surface 67 formed on said element 50. The passages preferably extend radially relative to the arcuate inner face 53.

Punches 69 slidably t in these passages, said punches having inner ends 71 and outer ends 70. The outer ends of the punches are connected by welding or other means to a flat punch plate 72 which, when positioned against outer surface 67 properly locates the punchesiso that they will extend at their punching ends 71 a predetermined distance inwardly beyond the inner face 53 of element 50.

The punch plate is mounted on one end 73 of an elongated relatively large diameter shaft 74 which extends in axial parallelism with the punches 70, said shaft being reduced at its said end 73 to form an elongated reduced portion 75 terminating in an annular shoulder 76. This shaft 74 is slidably received in a bore 78 formed through a heavy guide block 79 which is shorter in length than said shaft so that end 73 of the latter and its opposite end 80 extend outwardly out of opposite ends of the bore 78.

Siidably mounted on the reduced end portion 75 for movement between the punch plate 72 andVV annular shoulder 76 is a retractor plate 81. To the retractor plate 81 are secured a pair of elongated rods 82 which slidably extend parallel to the shaft '74 through suitable passages formed through the guide block 79. These rods extend at their ends 83 beyond the end 80 of the shaft, said ends 83 being threaded. A retractor bar 87 is tted over the threaded ends 83 of the rods 82 and secured against longitudinal movement relative thereto by means of nutS 83 threaded thereover. The bar 87 is positioned so that it normally is spaced outwardly of the end 80 of the shaft 74.

The guide block 79 is mounted on an inclined bracket 90 secured to or formed as an integral part of the table top 11, said bracket being provided with a plurality of elongated apertures 92 through which machine bolts 93 are extended and threaded into suitably tapped sockets formed in the guide block 79, said apertures 92 permitting a certain limited adjustability of the guide block 79 relative to the tube engaging element 50.

Mounted opposite each other on a brace 13 are a pair of punch operators or hammer members 97 and 98. Operator 97 has a pair of armsr100 and 101 extending substantially at right angles to each other and is mounted for swinging movement in a vertical plane on a pin 102 which extends through a suitably located aperture formed through the operator 97 at the juncture of arms 100 and 101. Arm 100 is positioned so that its free end 103 extends upwardly between, and in spaced apart relationship to the bar `87 and the end 80 of the shaft 74. Arm 101 which serves as a lever arm extends beneath the table top 11, its free end 104 being bifurcated to form a pair of spaced apart fingers 105 and 106, respectively, said fingers being provided at their ends with rollers 107 and 108 rotatably mounted on stub pins 109 and 110, respectively. Operator 98 shown in FIGURE 1 and partially in FIGURE 2 is identical to operator 97 but mounted in counterposed relationship thereto, having a bifurcated free end 111 of an arm 112 which, like the bifurcated free end 103 of arm 100, is provided with roller bearing fingers 113 and 114.

A drive shaft- 118 is suitably mounted beneath the table top 11 for rotation in bearings 119 and 120 secured to brace elements 13, said shaft having a cam 122 nonrotatably secured thereon by any suitable means, said cam extending between the t'ingers at the free ends 104 and 111 of the arms 101 and 112, respectively, so as to r0- tatably engage the rollers of each of the latter. The cam 122 is formed as to have variable eccentricity, with an advance surface 123, relative to the roller or finger 106, having a larger radius of curvature than the following surface 124.

A flywheel 125, see FIGURES 1, 2 and 4, is mounted on suitable bearings 126 on the shaft 118 for free rotation relative thereto, said ilywheel being belt-driven from an electric motor 128 secured to the supporting frame 10 and connected to a suitable source of electric power.

The flywheel has non-rotatably secured thereto an internally toothed pawl ring 130, see FIGURES 2, 3 and 4, in spaced concentric relationship with the shaft 118.

Mounted on thel drive shaft 118 is a pawl device 131. This device includes a pawl carrier 132 in the form of a disc which is non-rotatabiy secured to the shaft 118 by any suitable means, such as by welding thereto or by set screws or the like. A pawl 133 is swingably mounted on a pin 134 extending laterally from the carrier 132 adjacent the periphery of the latter, the pawl being swingable between a retracted position against the peripheral surface of the carrier 132 as illustrated in solid lines in FIGURE 3, and an extended position as illustrated in dotted lines in FIGURE 3, wherein it is swung outwardly from said peripheral surface into engagement with the pawl ring 130. A compression spring 135 is positioned under compression between the carrier 132 and the pawl 133 normally urging the latter outwardly to its last-mentioned position. The width of the pawl is such that a portion 136 thereof projects outside of and clear of the pawl ring E30.

The movement of the pawl 133 between its extended and retracted positions is controlled by means of a pawl operator 137. This pawl operator has an elongated pawl engaging arm 138 swingably mounted at one end 139 for swingablemovement in a horizontal plane on the shank of a pin 140, the latter being suitably secured to a bracket 141 extending from supporting frame 10. The arm 138 may be swung between positions into and out of the path of pawl portion 136. Referring to FIGURE 3, the arm 138 is illustrated as being positioned in the path of the pawl (shown in solid lines) thereby preventing the latter from engaging the pawl ring. When the arm is swung out of the path of the'ipawl, the latter will automatically swing into engagement with the pawl ring to be rotated by the latter until the arm 138 is again swung into the path of the pawl and disengage the pawl and pawl ring. A lever 142, connected to the arm 138 and spring-urged by a compression spring 143 extending between said lever 142 and bracket 141, normally urges the pawl engaging arm 138 to a pawl engaging position in the path of the pawl. A cable 144 is secured to the lever 142 providing means whereby the arm may be swung against the spring 143 to a position out of the path of the pawl.

It will be seen that the pawl and pawl ring serve as a clutch by means of which the drive shaft and motor may be placed in an engaged or disengaged condition thereby permitting continuous operation of the motor without affecting the drive shaft when the pawl and pawl ring are not engaged.

The drive shaft 118 is also provided with a brake device 150 (see FIGURES 2 and 5). This brake device is preferably of the friction type as is illustrated in FIGURES 2 and 5, and comprises a pair of brake shoes 152 and 153 provided with brake linings 154 and 155, respectively, which are arranged in complementary relationship about the shaft 118. Shoe 152 is connected by braces 156 to the supporting frame 10, and shoe 153 is adjustably connected to shoe 152 by means of draw bolts 158. The brake device 150 is adjusted so that it will permit the drive shaft to be rotated when engaged with the motor 128 but will immediately stop the rotation of the drive shaft when the engagement of the latter and the motor is severed by disengagement of the pawl with the pawl ring.

In the operation of the tube perforator, the gripping elements 35 and 36 are first positioned so that the tube is firmly and intimately engaged by said elements and gripping elements 50 and 51 with the punches in their retracted position. The pawl operator 137 is then momentarily moved out of its pawl engaging position so as to permit the pawl to engage the rotating pawl ring. The pawl operator is then permitted to swing back to its normal position under the action of the spring 143 into the path of the pawl so as to engage the latter, after the drive shaft completes one revolution, thereby disengaging the pawl and the rotating pawl ring and thereby permitting the brake device 150 to bring the shaft 118 to a stop.

During one revolution of the shaft 118, the rotation of the cam will result in swinging movement of the operator 97 first moving the end 103 of the arm 101 into engagement with the end 80 of the shaft 74, thereby driving the latter and with it the punches 70 inwardly so as to perforate the tube 45 and then moving the arm 101 outwardly against the bar `87 thereby drawing its retractor plate 81 against the annular stop 76 to withdraw the punches. The piston and cylinder assembly 28 is then operated to release the grip o'f the gripping elements 35 and 36 and 50 and 51 upon the tube, and the latter is rotated to permit another punching operation to be carried out.

It will be observed that the shaft 74 moves linearly whereas the arm 100 of the operator 97 swings. However, as the arm 100 is not connected directly to either of the shaft 74 or the bar 87, the binding effect normally resulting from a direct connection of a linearly moving body with a swinging body, is eliminated. The arm i), in effect, acts in the nature of a hammer which when swung back and forth through the operation of the cam rst strikes the end 80 of said shaft 74 so as to drive the punches to an extended position relative to the member 50 and then strikes the bar 87 to pull the retractor plate against the annular shoulder 76 so as to withdraw the punches 70 from their extended position.

It will be further observed that the variable eccentricity of the cam will result in a rapid movement of the arm 100 as the latter is driven against the shaft 74. The punches will, consequently, be snapped to their extended position.

It wil be understood that the foregoing description of the operation of the punches 70 in element 50 will apply to the operation of their counterparts in element `51 through the operational engagement of punch operator 98 with the cam 122 and with punching mechanism 160 similar to punching mechanism `52.

The tube perforator is peculiarly adapted to perforate the walls of large diameter thin walled helically corrugated drain pipes, although it may advantageously be employed to perforate pipes having either smooth walls or standard circular corrugated walls. When the perforator is used to perforate the first-mentioned type of pipe, gripping elements (35, 36; 50, 51) whose inner faces are provided with helically oriented corrugations matching the corrugations of the pipe, are employed so as to provide intimate contact of said inner 'face with the wall of the pipe. These inner faces consequently cooperate with the wall of the pipe so that upon rotation of the latter, after a punching operation is completed, the pipe will automatically advance through the tube gripping elements. The need for equipment to move and adjust the pipe linearly is thereby eliminated.

In order to perforate a smooth wall pipe, it is only necessary to replace the tube gripping elements, having the helically corrugated inner faces, with the tube gripping elements having smooth inner faces. In view of the fact, however, that smooth walled pipes are prone to collapse in a perforating operation, an expandable inner tubular support (see FIGURE 6) is employed. This tubular support is formed of a length of spring steel, longer than the pipe to be perforated, slit longitudinally and being normally, in a state of repose, la little larger in diameter than the pipe to be perforated. This support 160 is formed having a plurality of longitudinally extending internal slots 161 formed therethrough in a position corresponding to the pattern in which it is intended to perforate the pipe.

In order to use the tubular support, the latter is first collapsed against its natural resiliency to a diameter small enough to permit its insertion within the pipe to be perforated and then permitted to expand outwardly against the inner wall of the-pipe so as to lend support to the latter. After the pipe has been perforated, the support 160` is again collapsed and withdrawn.

As a further safeguard against the collapse of smooth walled or corrugated pipes, the punches carried by each punch plate are of different length so that the punches will strike the pipe to be perforated in consecutive order rather than simultaneously so that excessive force will not be applied to the pipe at any one time.

What is claimed is:

1. Tube perforating apparatus comprising a supporting frame, first and second tube engaging members mounted in confronting relationship on the frame, said members having arcuately shaped inner faces in confronting relationship for intimately engaging and holding a tube to be perforataed, one of the members having at least one guide passage extending therethrough radially of the inner face thereof, a punch slidably located in the guide passage for movement between extended and retracted positions relative to the inner face of said one member, a punch carrier slidably supported on the frame for movement in the direction of movement ot' the punch and being operably connected to the latter, a retractor operably connected to the punch carrier, a hammer member swingably mounted on the frame for operation between the carrier and retractor, said hammer member being adapted when swung in one direction to strike the carrier and move the punch to its extended position and when swung in the opposite direction to strike the retractor so as to move the carrier and with it the punch to its retracted position, and operator controlled means for operating the hammer member.

2. Tube perforating apparatus as claimed in claim 1 including operator controlled means for moving the tube engaging members into and out of engagement with a tube to be perforated so as to permit the latter to be repositioned relative to the punch after a punching operation.

3. Tube perforating apparatus comprising a supporting frame, a pair of tube engaging members mounted on the frame in confronting relationship, one of said members being stationary and the other -being movable towards and away from said one member, said members having arcuate inner faces in confronting relationship foi intimately engaging a tube to be perforated and the stationary member having at least one radial guide passage extending therethrough, a punch slidably located in the passage extending therethrough, a punch slidably located in the passage for reciprocal movement between extended and retracted positions relative to the inner face of the fixed member, a punch carrier connected to the punch and being slidably supported on the frame for reciprocal movement, a linearly movable retractor operably connected to the punch carrier, a hammer member swingably mounted on the frame for movement between the punch carrier and retractor, said hammer member being adapted when swung in one direction to strike the carrier so as to move the punch to its extending position and when swung in the opposite direction to strike the retractor so as to move the carrier and with it the punch to its retracted position, and operator controlled means for swinging the hammer member.

y4. Tube perforating apparatus as claimed in claim 3 including operator controlled means for moving the movable tube engaging member out of and into engagement with a tube to be perforated so as to permit the latter to be repositioned relative to the punch after a punch operation.

5. Tube perforating apparatus as claimed in claim 3 in which the fixed member is provided with a plurality of guide passages and said carrier is provided With a plurality of punches, said punches being of varied lengths so as to consecutively engage the tube to be punched during a punching operation.

6. Tube perforating apparatus as claimed in claim 3 including a rigid tubular expandable supporting member for slidably fitting into the tube for providing support for the latter during a punching operation, said supporting member being provided with longitudinally extending openings to permit the passage of the punch therethrough during a punching operation.

7. Tube perforating apparatus as claimed in claim 3 in which the operator controlled means comprises a drive shaft, a flywheel freely rotatably on the drive shaft and connected in drive engagement with a motor, a pawl ring connected to the flywheel for rotation therewith, a pawl connected to the drive shaft for rotation therewith, resilient means normally urging the pawl into engagement with the pawl ring so as to place the drive shaft in driven engagement with a flywheel, a pawl operator swingably mounted on the frame being adapted when positioned in the path of the pawl to disengage the latter and the pawl ring, a cam nonrotatably mounted on the drive shaft, an elongated lever connected at one end to the hammer member, and cam follower means at the other end thereof engaged with the cam.

8. Tube perforating apparatus as claimed in claim 7 in which the cam is variably eccentric having an advance surface formed as to have a greater radius of curvature than its following surface so as to provide for rapid move- Trient of the hammer member towards the punch carrier.

9. Tube perforating apparatus as claimed in claim 3, in which the confronting faces of the tube engaging memaers are provided with helical corrugations for intimately fitting a helically corrugated tube to be punched.

10. Tube perforating apparatus comprising a supportng frame, a pair of tube engaging members mounted on :he frame in confronting relationship, one of said mem- Jers being stationary and the other being movable towards ind away from said one member, said members having ircuate inner faces in confronting relationship for intinately engaging a tube to be perforated and the stationiry member having at least one radial guide passage zxtending therethrough, a punch slidably located iii the vtissage for reciprocal movement between extended and retracted positions relative to the inner face of the fixed member, a punch carrier connected to the punch and being slidably supported on the frame for reciprocal movement, a linearly movable retractor operably connected to the punch carrier, a hammer member swingably mounted on the frame for movement between the punch carrier and retractor, said hammer member being adapted when swung in one direction to strike the carrier so as to move the punch to its extended position and when swung in the opposite direction to strike the retractor so as to move the carrier and with it the punch to its retracted position, a drive shaft rotatably 4mounted on the frame, operator controlled means for rotating the drive shaft, a cam mounted on the drive shaft for rotation therewith, and means operably connecting the hammer member and cam for swinging the hammer member as the cam rotates.

11. Tube perforating apparatus as claimed in claim 10 in which the operator controlled means comprises a flywheel freely rotatable on the drive shaft and connected in driven engagement with a motor, a pawl ring connected to the flywheel for rotation therewith, a pawl connected to the drive shaft for rotation therewith, resilient means normally urging the pawl into engagement with the pawl ring so as to place the drive shaft in driven engagement with the flywheel, and a pawl operator swingably mounted on the frame and being adapted when positioned in the path of the pawl to disengage the latter and the pawl ring.

12. Tube perforating apparatus as claimed in claim 10 in which said last-mentioned means comprises a lever arm operably connected to the hammer member for swinging movement therewith, said lever arm having a bifurcated free end embracing the eccentric so as to result in oscillatory motion of said lever arm as the eccentric is rotated.

13. Tube perforating apparatus as claimed in claim 10 in which the cam is variably eccentric having an advance surface formed as to have a greater radius of curvature than its following surface so as to provide for rapid movement of the hammer member towards the punch carrier.

14. Tube perforating apparatus as claimed in claim 10 including a resilient tubular expandable supporting member for slidably fitting into the tube for providing support for the latter during a punching operation, said supporting member being provided with longitudinally extending openings to permit the passage of the punch therethrough during a punching operation. 1S. Tube perforating apparatus as claimed in claim 10 1n which the confronting faces of the tube engaging members are provided with helical corrugations for intimately fitting a helically corrugated tube to be punched.

16. Tube perforating apparatus comprising a supporting frame, a pair of tube engaging members mounted on the frame, in confronting relationship, one of said members being stationary and the other being movable towards and away from said one member, said members having arcuate inner faces in confronting relationship for intimately engaging a tube to be perforated, and the stationary member having at least one radial guide passage extending therethrough, a punch slidably located in the passage for reciprocal movement between extended and retracted positions relative to the inner face of the fixed member, an elongated shaft connected at one end to the punch, said shaft having longitudinally spaced apart stops, a guide block mounted on the frame having a guide passage through which the shaft slidably extends, a retractor plate slidably mounted on the shaft for movement between the stops, a pair of retractor rods slidably extending through passages formed in the guide block, each rod being connected at one end to the retractor plate and extending at its other end beyond the other end of the shaft, a retractor bar extending between and connected to said other ends of the rods, an elongated hammer member swingably mounted on the frame at one end and extending at its other end between the retractor bar and the other end of the shaft, said hammer member being adapted when swung in one direction to strike the shaft and thereby move the punch to its extended position and when swung in the opposite direction to strike the retractor bar so as to move the shaft and thereby withdraw the punch to a retracted position, and operator controlled means for swinging the hammer member.

17. Tube perforating apparatus as claimed in claim 16 in which the operator controlled means comprises a drive shaft, a flywheel freely rotatable on the drive shaft and connected in driving engagement with a motor, a pawl ring connected to the flywheel for rotation therewith, a pawl connected to the drive shaft for rotation therewith, resilient means normally urging the pawl into engagement with the pawl ring so as to place the drive shaft in driven engagement with the ywheel, a pawl operator swingably mounted on the frame being adapted when positioned in the path of the pawl to dsengage the latter and the pawl ring, a cam non-rotatably mounted on the drive shaft, an elongated lever connected at one end to the hammer member, and cam follower means at the other end thereof engaged with the cam.

18. Tube perforating apparatus as claimed in claim 16 including operator controlled means for moving the movable tube engaging member out of and into engagement with the tube so as to permit the latter to be repositioned relative to the punch after a punching operation.

in which the fixed member is provided with a plurality of guide passages and said carrier is provided with a plurality of punches, said punches being of varied lengths so as to consecutively engage the tube to be punched during a punching operation.

20. Tube perforating apparatus as claimed in claim 16 including a resilient tubular expandable supporting member for slidably iitting into the tube for providing support for the latter during a punching operation, said supporting member being provided With longitudinally extending openings to permit the passage of the punch therethrough during a punching operation.

21. Tube perforating apparatus as claimed in claim 16 in which the confronting faces of the tube engaging members are provided with helical corrugations for intimately fitting a helically corrugated tube to be punched.

References Cited UNITED STATES PATENTS 2,325,437 7/ 1943 Temple 83--194 2,326,536 8/1943 Hartsock et al 83--193 X FOREIGN PATENTS 214,750 10/1909 Germany.

JAMES M. MEISTER, Primary Examiner U.S. C1. XR.

19. Tube perforating apparatus as claimed in claim 16 30 83-454, 513, 526, 616 

